As to the stereoscopic video display apparatus, which is the so-called three-dimensional display, various schemes are known. In recent years, demands for a scheme which is for a flat panel type and which does not need dedicated glasses have increased. In stereoscopic moving picture display apparatuses of this type, there are also apparatuses which utilize the principle of the holography. However, it is difficult to put them to practical use. A scheme in which an optical plate is installed immediately before a display panel (plane display device) having fixed pixel positions, such as a direct view type or projection type liquid crystal display device or plasma display device, to control light rays supplied from the display panel and direct the light rays to a viewer is known as a scheme which can be implemented with comparative ease.
The optical plate is typically called parallax barrier as well. The optical plate controls light rays to make different images visible from different angles even in the same position on the optical plate. Specifically, in the case where only lateral disparity (horizontal disparity) is given, a slit or lenticular sheet (cylindrical lens array) is used. In the case where up-and-down disparity (vertical disparity) is also included, a pinhole array or a lens array is used. The schemes using the parallax barrier are further classified into the binocular scheme, multiview scheme, super-multiview scheme (super-multiview condition of the multiview scheme), and integral photography (hereafter referred to as IP as well). The basic principle of them is substantially the same as the principle which has been used in stereoscopic photograph invented approximately 100 years ago.
Among them, the IP scheme has a feature that the degree of freedom of the viewpoint position is high and the stereoscopic view can be obtained easily. In the IP scheme in which there is only horizontal disparity and there isn't vertical disparity, it is also possible to implement a display device having high resolution with comparative ease. On the other hand, in the binocular scheme and multiview scheme, there is a problem that the range of the viewpoint position which allows stereoscopic view, i.e., the viewing zone is narrow and it is hard to view. However, the configuration of the stereoscopic video display apparatus is the simplest, and the display image can be generated simply.
In such a direct view type autostereoscopic video display apparatus using a slit or lenticular sheet, moiré or color moiré is apt to be generated by interference between a periodic structure of optical apertures of the optical plate and a periodic structure of pixels of the plane display device. As its countermeasure, a method of inclining the direction of extension of the optical apertures obliquely is known.
However, installing the optical part of the optical plate obliquely poses a problem that the number of subpixels forming RGB for displaying an elemental image which is a set of parallax images assigned to the same optical aperture decreases, and the resolution is lowered as compared with the case where the optical apertures of the optical plate are installed vertically.